How many prints can you get from a 1 kg spool?

1. Start with whole-job grams

Slice the actual model with the selected printer, material, orientation, supports, and other job features. Prusa’s first-print workflow describes checking the selected configuration and the sliced result. An estimate from a different nozzle or profile is not automatically transferable.

“Floor” means round down to a whole number. If the calculation gives 8.8, plan eight complete jobs under those assumptions. The remaining fraction is material for a smaller job or another purpose, not a ninth complete copy.

The spool’s labeled net filament mass excludes its empty reel and packaging. A product sold as a 1 kg spool is not necessarily 1 kg when the full reel is placed on a scale.

2. Compare simple yield scenarios

For the 80 g example, 950 ÷ 80 = 11.875, so the plan contains 11 whole jobs. After those jobs, 120 g remains in total: the 50 g reserve plus 70 g left because another whole job would exceed the planned allowance.

The 50 g reserve is an example, not a standard margin. Choose a margin that reflects how uncertain your remaining weight and consumption estimate are.

3. Include material that is not in the finished object

Imagine a finished object uses 35 g, supports use 8 g, and a brim uses 2 g. The job consumes 45 g before any additional purge or loading allowance. With 950 g available after a reserve, floor(950 ÷ 45) gives 21 jobs. Dividing by the object’s 35 g alone would misleadingly suggest 27.

For a multicolor example, evaluate each spool separately. Suppose the slicer assigns 45 g of model, support, and brim material plus 25 g of purge-related use to one particular spool. That spool supplies 70 g per job, so its 950 g allowance can support at most 13 jobs. If another required color has only 100 g available and uses 10 g per job, the complete batch is limited to 10 jobs. These invented quantities show why total filament across all colors is not enough to predict yield.

Prusa’s wipe-tower documentation explains that its tower use relates to color changes and can be shared across multiple objects. Consequently, slicing four copies together may consume a different amount than multiplying a single-copy estimate by four. Slice the actual batch and inspect each filament’s total.

4. Estimate what remains on a partly used spool

When the empty reel’s mass is known, subtract it from the current total mass. For example, an assumed current reading of 480 g minus a documented 230 g empty reel leaves an estimated 250 g of filament. Do not borrow a tare weight from a reel with a different construction.

Account for attachments that were not included in the empty-reel measurement. Labels, adapters, and reusable spool parts can otherwise distort the subtraction. If the empty weight is unknown, record the uncertainty instead of reporting a precise remaining amount.

A transparent spool’s visual fill level is a rough clue. The same apparent thickness of winding does not contain a constant mass throughout the spool. For a near-limit job, a defensible weight estimate is more useful than “it looks half full.”

5. Keep reserves and failure history distinct

A reserve protects a particular planning estimate. A failure allowance reflects material consumed without producing usable parts. They answer different questions, and neither guarantees success.

Suppose a hypothetical batch consumes 360 g over all attempts and yields six accepted parts. The observed average is 360 ÷ 6 = 60 g per accepted part, including that batch’s failures. Do not add the same failed material again when evaluating the batch.

Keep both the original sliced estimate and the real outcome in the print log. A few unusually difficult jobs are not enough to claim a universal failure rate, but they are relevant to planning another identical batch.

6. Improve yield by changing the actual job

Compare a support-saving orientation, an appropriately sized model, or a justified change in walls and infill. Prusa explains that infill affects material consumption as well as the support beneath top layers. Removing it blindly can create another failed print.

Re-slice each candidate and compare the complete material totals, not just an infill percentage. Preserve the function and finish the project needs. A smaller number in the slicer is not a saving if the result is unusable.

Check the printer’s documented runout and spool-change behavior before relying on it. For multicolor jobs, verify every required spool separately; plentiful filament in one color cannot automatically replace a shortage in another. Once the quantities are sound, enter them in the cost calculator to translate the plan into material cost.